/Engine/Source/Runtime/GeometryFramework/Public/Components/DynamicMeshComponent.h
This function updates vertex positions/attributes of existing SceneProxy render buffers if possible, for the given triangles. If aFMeshRenderDecompositionhas not been explicitly set, call is forwarded toFastNotifyVertexAttributesUpdated()
void FastNotifyTriangleVerticesUpdated ( const [TSet](API\Runtime\Core\Containers\TSet)< int32 > & Triangles, EMeshRenderAttributeFlags UpdatedAttributes )